Higher education organizations are increasingly playing a key role in promoting Sustainable Development within society by disclosing information about applied strategies and achieved sustainable performance via social media. Consequently, platforms like Twitter have evolved into decisive tools for fostering accountability, establishing legitimacy, and displaying engagement to environmental sustainability. First, this paper aims to analyze the impact of published sustainable content on Twitter on the stakeholders' online engagement level within British green universities ranked by the People & Planet University League. Second, the study intends to investigate the influencing factors that enhance online interactions. To attain the purpose a theoretical framework was established and a text mining analysis of 145,941 tweets was conducted to construct both a sustainable and a general online engagement index. Finally, a multivariate regression analysis was employed to create two models based on content type. The results reveal a heightened interest in engaging with sustainable content shared on the official Twitter profiles of the sampled universities in comparison to general information tweets. Furthermore, the findings indicate that organizational attributes, reputational factors, and considerations related to strategy design and implementation of sustainable policies, along with the sentiment polarity of the disseminated content, contribute to elucidating the attained level of online engagement. These factors work together to involve stakeholders in the pursuit of sustainable development goals within Green Universities.